"From then on it's pretty wide open," said Jeffrey Rudolph, president of the center. But Rudolph declined to give a time frame for Endeavour’s arrival at the Science Center.

The spacecraft's wings came within inches of the trees, forcing crews to do last-minute trims. In the predawn darkness, a crewman shined a flashlight on the tip of Endeavour's wingspan, which is so broad that it often hung over the boulevard’s sidewalks.

Hour by hour, the delays of Endeavour seemed to stretch even longer. On Saturday afternoon, the shuttle was only three hours behind its scheduled arrival of 9 p.m. that night. But by 2:30 a.m. Sunday, it was about eight hours behind schedule, making it possible that Endeavour would arrive well after Sunday breakfast plates had been cleared away.

The seemingly interminable delays wore on the police officers who were escorting the shuttle, who had now been working 18 or 19 hours. They appeared weary, with baggy eyes. A fleet of 12 LAPD cruisers sat behind the shuttle, as one fatigued officer riding shotgun rested his elbow on the window edge, resting his head on his fist.

A team of replacement officers, who were working their regular 7 p.m. to 7 a.m. shifts, were called in to provide relief at the last moment and were ordered to stay with Endeavour until it reached the California Science Center museum.

When it would actually arrive, no one knew for certain.

"We're used to stuff like this," said LAPD Sgt. Kate Stanwix, one of those brought in to relieve her colleagues. "What's the use of complaining?"

George Martin, 55, was standing on the sidewalk on Martin Luther King Jr. Boulevard when the shuttle passed Leimert Park shortly before 6 a.m.

“We waited all day and night, and it finally got here,” Martin said, as he gazed toward the shuttle coming down the boulevard.

Martin, who had staked out his spot at 11 a.m. on Saturday, said the wait was worth it.

“Oh, yeah, you're never going to get to see it again,” he said. “This is it.”

Officials had known the path of Endeavour on the first stretch of Martin Luther King Jr. Boulevard would be difficult. They decided they wanted to protect the trees planted in honor of the slain civil rights leader, so they designed a complex series of zigzag, crab-like movements to pass Endeavour through the relatively narrow road.

At one point, crews lowered the shuttle just to avoid a leafy tree — and the spacecraft was able to sneak under a branch. Workers only had to snip off a bit of the bark.

"Amazing they can control this machinery to control this huge spaceship — how they can save the tree — that was like inches," said Eleuterio Rojas of Leimert Park, moments after the shuttle's right wing cleared a tree by about an inch or so in front of Audubon Middle School.